Because you are consuming a service we are providing, the same way we are required to have logins with Apple and Google and pay them yearly fees to use their push notifications services. These services have polices we have to follow, and in order to do so, we need to control the usage of our gateways.
You are welcome to cut the middle man, us, and deal directly with them.
What part of that is so hard to understand?
Why odd? The instances were not storing local data about the usage of push notifications, but we were able to measured usage by counting hits form workspace IDs to the service.
This is factually incorrect. You can change the setting for the server not to send push notification on ALL MESSAGES by default, and only on mentions. User can override that per account or per channel. Are you not aware of this possibility?